[CriticalMass]

I can't make that check because the DMM I have will not test for amperage that high.

I agree that the bench test doesn't prove the starter is performing correctly, but it would rule out the starter as the source of the problem I described above. Half the time the solenoid engages, half the time it does not. Futhermore, on the occasions that it does engange, I'll usually hear the clicking for a second or two, and then it cuts off.

The starter is under no load during engagement of the solenoid, so the bench test would replicate its function during that phase of operation (with the exception that it may receive less voltage/current from the ignition wiring system...but then that would be the source of the problem). The only cause (that I can think of) is that it is not receiving reliable electric flow, as it does in the bench test.